Former FBI director James Comey’s credibility as a witness in the investigation into President Donald Trump’s possible obstruction of justice threatens Trump’s presidency. Comey paints a detailed, remarkably believable portrait of Trump’s efforts to entice Comey to look the other way in the Michael Flynn matter; his contemporaneous notes and other witnesses (some of whom Comey deliberately created by sharing events in real time with them) all further bolster his credibility. His honesty will be hard to call into question; hence, Trump’s flurry of Sunday tweets revealing the depths of the president’s panic.

By the way, his bracing honesty extends beyond Trump. He rightfully observes that Deputy Attorney General Rod Rosenstein was used to cook up a false pretext for firing Comey. (“The deputy attorney general, in my view, had acted dishonorably by putting out this pretext about why I was fired.”) His take on Attorney General Jeff Sessions was equally candid and eerily accurate. (“My sense of him, maybe it’s unfair to him, was that he was overmatched for the job. And — that the job was … much, much bigger than he was. And that he was going to struggle in it.”)

However (and this, ironically, may be the main conclusion that the public draws from Comey’s book tour), his judgment — not the accuracy of what he says, but the decisions drawn from his observations — frequently is downright awful. Consider:

He writes a book heavy on personal insults and promotes it with sensational speculation (e.g., Trump was compromised by Russia). He thereby turns the most serious constitutional confrontation since Watergate into a three-ring circus. We may share his disgust with Trump (“morally unfit”), but such remarks also display Comey’s bias, something a competent legal team would exploit. In an interview broadcast Sunday with ABC, he is remarkably obtuse on this point:

GEORGE STEPHANOPOULOS: You’ve been interviewed by Robert Mueller?

JAMES COMEY: I’m not going to talk about my contact with the special counsel.

STEPHANOPOULOS: You’re free to do to that. Correct?

COMEY: Yes, but I also want to make sure that I — don’t — I don’t do anything that might get in the way of their ability to be effective.

STEPHANOPOULOS: Do you think there’s any chance that — that writing this book will get in the way?

COMEY: I don’t know. I hope not. I mean, because I’ve tried to be consistent. What you worry about with interviews or with — with — with a witness writing a book is, does their story change? And again, that’s the virtue of the memos, is that I’ve tried to be true to the memos and not create inconsistent statements.

Really, he doesn’t see that expounding at length in highly negative terms about Trump couldn’t create problems for the special counsel?

Comey still lacks an appreciation for the damage he did in 2016 by providing an extensive explanation for not recommending that Clinton be prosecuted, accusing her of “extreme carelessness” and testifying to Congress.

STEPHANOPOULOS: So if no prosecutor would prosecute this case, why not put out a one-line statement, “We decline to prosecute”?

COMEY: Yeah. It’s a great question and a reasonable question. And the reason I thought that would be inappropriate is the faith and confidence of the American people in the Department of Justice and the FBI are at the core of those organizations. If they’re not believed to be honest, independent and competent, they’re done.

If you issue a one-liner from the Obama Justice Department about one of the two candidates for president of the United States, in this case the Democratic nominee for president of the United States, and say, “We’re done here,” in the absence of any kind of transparency, corrosive doubt creeps in that the system is rigged somehow.

Comey never recognizes that expounding on the decision not to recommend prosecution and giving his personal opinion of Clinton’s conduct also shook the “faith and confidence” of the public. Likewise, making the announcement himself, rather than allowing the Justice Department to do so, smacks of excessive self-regard:

STEPHANOPOULOS: Your critics say this is where your ego got the best of you. This was your original sin?

STEPHANOPOULOS: Your critics say you offered way too much information. The way they put it, “Listen, in the FBI we simply do not bloody up people we choose not to prosecute.”

COMEY: Yeah, and I get that. Look, that’s fair criticism. But here — here’s my response to it. The Department of Justice has long done that in the appropriate case, where it’s necessary to the credibility of the work. There was controversy for the first couple years of my time as director over whether the IRS had targeted Tea Party groups.

Again, he envisions himself as the knight in shining armor, duty-bound to save the department and FBI. In reality, he did far more damage to both institutions by playing savior.

Comey’s worst error came 11 days before the election, when he popped up with evidence (Huma Abedin’s e-mails) that turned out to be much ado about nothing. Comey inadvertently reveals he acted in part to protect his own hide from accusations that he misled Congress (which flowed from his misguided decision to spell out why he didn’t recommend prosecution). Comey says he and the FBI would have been accused of concealing the newly discovered trove of e-mails:

COMEY: That’s an affirmative act of concealment, right? Because I’ve told Congress and the American people — the whole point of July 5th was transparency. “Look, American people, what we’ve done. We did it carefully, we did it well. There’s no there there. You can take that to the bank. You can rely on the FBI. We’re done. Everybody can get on with their lives.” It’s October 27th, that’s not true anymore, in potentially a huge way. So you could speak about it, or you could not speak about it. But the not speaking about it is an action.

STEPHANOPOULOS: Senior Justice officials weren’t convinced that you actually had an obligation to tell Congress that at that time. What was their argument, what was your response?

COMEY: Their argument was that it was not consistent with our policy, and that we don’t normally comment on investigations, all of which I agree with. And that they would advise against it. Actually never spoke to me about it personally. I had my chief of staff call over to the leadership’s chief of s- staffs of th- the attorney general and the deputy and say, “The director thinks that is between speaking and concealing. Speaking is really bad; concealing is catastrophic.

It never dawned on Comey he had it backward: Speaking was catastrophic. Moreover, he just knew Clinton would win: “Especially, given the world we’re operating in, when Hillary Clinton’s elected president? She’ll be an illegitimate president, but these organizations will never recover from that. You hid from the American people something you knew gave the lie to what you told them in Congress repeatedly.” Election prognostication is exactly what an FBI director should never do.

In sum, Comey is honest about events around him, but his self-righteousness prompted him to damage the institutions he cares so deeply about — and, worse, to tip the election in favor of a man he now calls “morally unfit.” His belief that a book tour would erase his reputation for reckless self-regard serves as another example of, well, his reckless self-regard.